|Originally posted by zambelli
Why do they do that? Is there an advantage to doing that versus just displaying each full original field every 1/60th of a second? Or is the latter impossible due to some technical limitation?
Perhaps I'm not thinking "analog enough" to understand this correctly, but it seems that the best way to display 1080i on a display capable of displaying only 540 lines would be to display the fields progressively at 60Hz. Sure, that'd be sacrificing vertical resolution for temporal resolution, but since the display can't actually handle the full vertical resolution anyway... that'd be as good as it can get, right?
Perhaps the reason the Toshiba is fixed at 540p is due to the fact there are lots of 720p broadcasts, and if one had to chose a native resolution that was a compromise between 720p and 1080i, 540p would be an intelligent choice.
For 1080i broadcasts, with the Toshiba displaying at 540p and the Sony displaying at 1080i, there is not going to be a large difference since we are getting 540 line frames per 60th second where the content (on the Toshiba) and line positioning (on the Sony) are changing ever so slightly from frame to frame.
For 720p broadcasts, the Toshiba is simply rescaling but maintaining the same cadence between the input frame and the displayed frame.
Alternately, when the Sony receives 720p, we have the same amount of scaling, but we are artificially forcing the odd number frames to be jumping down a half line thickness because we are creating an interlaced image. Doing this may cause some motion artifacts on the Sony that would not be visible on the Toshiba.